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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
commit03dd4cb26d967f9588437b0fc9cc0e8353322bb7 (patch)
treefa581f6dc1c0596391690d1f67eceef3af8246dc /kernel/bpf/hashtab.c
parentd4e493caf788ef44982e131ff9c786546904d934 (diff)
Linux-libre 4.5-gnu
Diffstat (limited to 'kernel/bpf/hashtab.c')
-rw-r--r--kernel/bpf/hashtab.c64
1 files changed, 38 insertions, 26 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 34777b374..c5b30fd8a 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -14,11 +14,15 @@
#include <linux/filter.h>
#include <linux/vmalloc.h>
+struct bucket {
+ struct hlist_head head;
+ raw_spinlock_t lock;
+};
+
struct bpf_htab {
struct bpf_map map;
- struct hlist_head *buckets;
- raw_spinlock_t lock;
- u32 count; /* number of elements in this hashtable */
+ struct bucket *buckets;
+ atomic_t count; /* number of elements in this hashtable */
u32 n_buckets; /* number of hash buckets */
u32 elem_size; /* size of each element in bytes */
};
@@ -79,34 +83,35 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
/* prevent zero size kmalloc and check for u32 overflow */
if (htab->n_buckets == 0 ||
- htab->n_buckets > U32_MAX / sizeof(struct hlist_head))
+ htab->n_buckets > U32_MAX / sizeof(struct bucket))
goto free_htab;
- if ((u64) htab->n_buckets * sizeof(struct hlist_head) +
+ if ((u64) htab->n_buckets * sizeof(struct bucket) +
(u64) htab->elem_size * htab->map.max_entries >=
U32_MAX - PAGE_SIZE)
/* make sure page count doesn't overflow */
goto free_htab;
- htab->map.pages = round_up(htab->n_buckets * sizeof(struct hlist_head) +
+ htab->map.pages = round_up(htab->n_buckets * sizeof(struct bucket) +
htab->elem_size * htab->map.max_entries,
PAGE_SIZE) >> PAGE_SHIFT;
err = -ENOMEM;
- htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct hlist_head),
+ htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct bucket),
GFP_USER | __GFP_NOWARN);
if (!htab->buckets) {
- htab->buckets = vmalloc(htab->n_buckets * sizeof(struct hlist_head));
+ htab->buckets = vmalloc(htab->n_buckets * sizeof(struct bucket));
if (!htab->buckets)
goto free_htab;
}
- for (i = 0; i < htab->n_buckets; i++)
- INIT_HLIST_HEAD(&htab->buckets[i]);
+ for (i = 0; i < htab->n_buckets; i++) {
+ INIT_HLIST_HEAD(&htab->buckets[i].head);
+ raw_spin_lock_init(&htab->buckets[i].lock);
+ }
- raw_spin_lock_init(&htab->lock);
- htab->count = 0;
+ atomic_set(&htab->count, 0);
return &htab->map;
@@ -120,11 +125,16 @@ static inline u32 htab_map_hash(const void *key, u32 key_len)
return jhash(key, key_len, 0);
}
-static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash)
+static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
{
return &htab->buckets[hash & (htab->n_buckets - 1)];
}
+static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash)
+{
+ return &__select_bucket(htab, hash)->head;
+}
+
static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash,
void *key, u32 key_size)
{
@@ -227,6 +237,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l_new, *l_old;
struct hlist_head *head;
+ struct bucket *b;
unsigned long flags;
u32 key_size;
int ret;
@@ -248,15 +259,15 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
memcpy(l_new->key + round_up(key_size, 8), value, map->value_size);
l_new->hash = htab_map_hash(l_new->key, key_size);
+ b = __select_bucket(htab, l_new->hash);
+ head = &b->head;
/* bpf_map_update_elem() can be called in_irq() */
- raw_spin_lock_irqsave(&htab->lock, flags);
-
- head = select_bucket(htab, l_new->hash);
+ raw_spin_lock_irqsave(&b->lock, flags);
l_old = lookup_elem_raw(head, l_new->hash, key, key_size);
- if (!l_old && unlikely(htab->count >= map->max_entries)) {
+ if (!l_old && unlikely(atomic_read(&htab->count) >= map->max_entries)) {
/* if elem with this 'key' doesn't exist and we've reached
* max_entries limit, fail insertion of new elem
*/
@@ -284,13 +295,13 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
hlist_del_rcu(&l_old->hash_node);
kfree_rcu(l_old, rcu);
} else {
- htab->count++;
+ atomic_inc(&htab->count);
}
- raw_spin_unlock_irqrestore(&htab->lock, flags);
+ raw_spin_unlock_irqrestore(&b->lock, flags);
return 0;
err:
- raw_spin_unlock_irqrestore(&htab->lock, flags);
+ raw_spin_unlock_irqrestore(&b->lock, flags);
kfree(l_new);
return ret;
}
@@ -300,6 +311,7 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct hlist_head *head;
+ struct bucket *b;
struct htab_elem *l;
unsigned long flags;
u32 hash, key_size;
@@ -310,21 +322,21 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
key_size = map->key_size;
hash = htab_map_hash(key, key_size);
+ b = __select_bucket(htab, hash);
+ head = &b->head;
- raw_spin_lock_irqsave(&htab->lock, flags);
-
- head = select_bucket(htab, hash);
+ raw_spin_lock_irqsave(&b->lock, flags);
l = lookup_elem_raw(head, hash, key, key_size);
if (l) {
hlist_del_rcu(&l->hash_node);
- htab->count--;
+ atomic_dec(&htab->count);
kfree_rcu(l, rcu);
ret = 0;
}
- raw_spin_unlock_irqrestore(&htab->lock, flags);
+ raw_spin_unlock_irqrestore(&b->lock, flags);
return ret;
}
@@ -339,7 +351,7 @@ static void delete_all_elements(struct bpf_htab *htab)
hlist_for_each_entry_safe(l, n, head, hash_node) {
hlist_del_rcu(&l->hash_node);
- htab->count--;
+ atomic_dec(&htab->count);
kfree(l);
}
}